超亲水纳孔分离膜的制备及其分子分离性能和稳定性研究

Superhydrophilic nanoporous membrane for highly efficient and stable separation of organic molecules

膜分离技术在有机分子污水的处理中具有广泛应用,其面临的难题之一是制备具有超亲水性质的纳孔膜以抵御有机污染物的污染,实现高效、稳定的分子分离.在本文中,我们通过全膜交联的方法在保持水凝胶纳孔膜超亲水性质的前提下大幅提升了其机械强度,制备了高强度超亲水纳孔膜.该膜实现了有机分子的高效分离,水通量达到220 L m^(-2)h^(-1)bar^(-1),考马斯亮蓝(CBB)截留率达到~99.9%,分子/盐(CBB/Na_(2)SO_(4))选择性达到747.在以腐殖酸为污染物的分子分离中,该膜表现出优异的抗污染性能,通量恢复率接近100%.该膜还具有出色的抗压性能,在高达8 bar的跨膜压力下保持了稳定的分子分离性能.本工作为制备超亲水纳孔膜实现有机分子废水的高效分离提供了一种新的思路.

Fabricating nanoporous membranes with superhydrophilic properties to overcome fouling from organic foulants is a challenge in membrane separation processes for organic molecules.Recently,researchers demonstrated that membranes with distinct hydrogel features exhibit superhydrophilicity and outstanding antifouling capacity.However,hydrogel membranes have low mechanical strength,which can lead to pore deformation and potential membrane rupture during pressure-driven separation processes.Herein,we report a whole-membrane crosslinking strategy to fabricate a superhydrophilic and robust nanoporous membrane in which polyethyleneimine is blended and crosslinked in a carboxylated polyacrylonitrile hydrogel membrane in situ.Wholemembrane crosslinking improves membrane strength,with crosslinking occurring both in the membrane interior and on the membrane surface.Efficient molecular separation with a water flux of 220 L m^(−2)h^(−1)bar^(−1),a Coomassie brilliant blue(CBB)rejection of~99.9%,and a CBB/Na_(2)SO_(4)selectivity of 747 was achieved with this membrane.The membrane also showed excellent antifouling capacity,with a flux recovery of~100%during molecular separation with humic acid as a foulant.At transmembrane pressures up to 8 bar,the membrane exhibited stable molecular separation.Our work provides a new route for fabricating superhydrophilic nanoporous membranes for the separation of organic molecules in wastewater.